Boat propeller unit



March 29, 1932" H RBsT- BOAT PROPELLER UNLT' Filed July 15, 1930 gwwntoc F. Hrfisi Patented Mar. 29, 1932 PATENT OFFICE rm amuse or wmrnaoamassacnosmrs Boar PBQPELLER mm Application filed July 15,

The present invention relates to propeller driving mechanisms and is an improvement.

over the propeller drive structure for boats disclosed in my application for boat propeller units, Ser- No. 336,473 filed J anuar 31, 1929 and allowed May 19, 1930.

An object of this invention is to provide a propeller drive unit by means ofwhich a plurality of oppositely drivenpropellers may be is operated from the same unit so that the present objectionable feature of the propeller of the boat drawing the rear end-of the boat downwardly into the water will be eliminated.

In the devices at present in use, where a single propeller is attached to a drive unit or where a single propeller is used in any boat driving mechanism, the pressure exerted by the propeller has a tendency to swing the boat in a circle. While the rudder ,of the boat overcomes this tendency of the propeller to. the boat in a circle, nevertheless in swin boats of the speed type where the engine is suddenly shut off, it frequently happens that the boat overturns due to the release of the pressure on the rudder and to the fact that the rudder is normally positioned at an angle to the longitudinal axis of the vessel. It is therefore another object of this invention to provide a propeller structure by means ofwhich a pair of reversely rotating propel lers'may be used in'either a push or a pull position, thereby compensating the pressure of one propeller to turn the boat in one direc tion by the pressure exerted by the other propeller which exerts the pressure in the opposite direction. a

A further-object of this invention is to provide a propeller mechanism which is soconstructed that it may be readily mounted on the stern of a vessel and which,' when mounted thereupon, in either deep or shallow water, therebygreatly increasin the cruising radius in shallow water 0 relatively large vessels will permit the vessel to operate 1930, Serial No. 468,154.

which now have a relatively deep draft due to the manner in which the propellers are mounted on the bottom of the vessel.

A still further object of this invention is to provide a'propeller mechanism which is so constructed that the pressure exerted by the propeller in the following stream is directed upwardly against the bottom of the unit and thereby has a, tendency to lift the stern of the boat and to prevent squatting of the stern through the rotating action of the propeller particularly at high speed.

A further object of this invention is to provide a boat propeller mechanism which is so constructed that when mounted on a boat it no will have a tendency to maintain the boat on a'relatively even keel from the stem to the stern'rather than to thrust the forward end of the boat out of water and pull the rear end downwardly in the water thereby holding the vessel at an angle to the surface of the water. At high speeds, this inclination of the boat in the water is relatively dangerous due to the action of the waves in striking the bottom of the boat adjacent the bow in and having a tendency to lift the bow with the passage of each wave. Where the vessel is maintained on an even keel, the bow of the boat is so constructed as to split the waves and to ride thereover. 75 The above and various other objects and advantages of this invention will in part be described in and in part be understood from the preferred embodiment of this invention;

Figure 2 is a sectional View partly in detail taken on the line 22 of Figure l Figure 3 is a fragmentary vertical sectional view partly-in detail; and

Figure 4 is a longitudinal sectional view of the device partly in detail.

Referring to the drawings wherein like numerals of reference designate corresponding parts throughout the several views, the numeral 10 designates a vertically disposed housing similar to the housing shown in my allowed prior application, and the numeral 11 designates a driven shaft which is mounted within the housing 10 in substantially vertically disposed position. A drive shaft 12.

is mounted in the upper end of the housing 10 and is connected to the driven shaft 11 by means of gears 13 and 14, the gear 13 being mounted on the drive shaft 12 and the gear 14'being mounted on the driven shaft 11. The

upper end of the housing 10 is provided with. a suitable cap or closure 15 and the interior of the housing 10 is preferably of hollow construction so as to provide a lubricant reservoir, the lubricant. being inserted into the housing 10 by means of a lubricant fitting 16 positioned in the cap 15. Y

Suitable lubricating channels are provided within the housing 10 so that the lubricant may readily pass through the entire housing and properly lubricate. all of the moving parts. The drive shaft 12 is suitably mounted ,on anti-friction bearings 17' and in like manner the driven shaft, 11 is rotatably mounted in the housing 10 on antifriction bearings 17. p V

'The lower end of the housing 10 terminates in a transversely disposed casing 18 of suitable configuration and a relatively large skew gear 19 is secured to the lower end of the driven shaft 11 and is adapted for rotation therewith. 'A pair of propeller shafts 20 and 21 are rotatably mounted in the casing 19 and provided with suitable anti-friction bearings 17 so as to eliminate so far as possible all friction of the shafts 20 and 21. The shafts 20 and 21 are provided with relatively small skew gears 22 and 23, the gear 22 being adapted to rotate oppositely or reversely from the gear 23, and coactively, the propeller shaft 20 rotates reversely from the propeller shaft 21.

A propeller 24 is secured to one endof the propeller shaft 20 and in like manner a second propeller 25 is secured to the propeller shaft 21, the propeller 24 rotating reversely to offer as little resistanceas possible to the water and in like manner the casing 18 is so constructed as to offer as little resistance as possible to the water.

In the operation of this device, the housing 10 is adapted to be secured to the stern of the vessel and the propellers 24 and 25 so 'mounted as to be of a pull or a tractor type ofthe drive--shaft-12 will coactivel rotate the driven shaft 11 through the gears 13 and 14 andthe' rotation of the driven shaft 11 will rotate theskew gear 19.

The pitch of the teeth of the gear 19 is such as toreadily and freely rotate the small skew gears 22. It will be obvious from the foregoing that in the rotation of the propellers 24.and 25, one. in opposite direction to the other, the swinging action of one propeller V is offset by the swinging action of the other propeller and that where the vessel is driven at'a1 relatively high speed, the suddenstoppage of the motor and the propellers will not cause the vessel to turn over or get out of control as is the case. where only one propeller is infuse. i i

While I have disclosed the present propeller structure with the propellers mounted on only one sideof the housing 10, these propellers being so synchronized that the blades thereof will freely rotate past each other,.I do not wish to be limited to this construction as if desired, one of the propellers may be mounted on the rear side of the casing 18 and the other mounted'on the forward side thereof, the propellers rotating one reversely from the other. These propellers, when mounted on the same side of the casing 18, may bemounted on either the forward or the rear side thereof depending only upon the use for which thepropeller structure is designed.

It is, of. course,,understood that various changes and modifications may be made in the details of constructionand design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claim:

What is claimed is z In a boat propelling unit including an upper housing, a horizontally disposed drive shaft rotatable therein, a verticalintermedi v ate housing, a driven shaft rotatably mounted in vertical position in said latter housing, and gears operatively connecting. said drive and driven shafts a lower horizontally disposed flat housing carried by said verticalhousing, atflatidisc-like gear member secured to-one end of said driven shaft and having curved teeth on the periphery thereof,'a pair of parallel propeller shafts mounted in said lower housing one on each side of said housing, gears on said latter shafts meshing with said curved teeth and adapted to turn said latter shafts one reversely from the other, and a propeller mounted one on each propeller shaft and positioned on the forward side of said lower housing, said propellers having the pitch thereof one reverse from the other, whereby to relieve the torsional strain on the vertical housing and steering mechanism.

In testimony whereof I hereunto alfix my signature.

FRANK HERBST. 

